In a case where passengers get into and off an aircraft (airplane) in an airport, a passenger boarding bridge coupling a terminal building to the aircraft is sometimes used.
The passenger boarding bridge includes a rotunda connected to a platform of the terminal building, a tunnel section having a base end connected to the rotunda and being extendable and retractable, and a cab (head) provided at the tip end of the tunnel section and connected to the aircraft.
The tunnel section includes a plurality of tunnels which are telescopically fitted to each other. The tunnel section is extendable and retractable over the entire length in a lengthwise or longitudinal direction. With this configuration, a change in a distance between the terminal building and the aircraft can be properly dealt with. In this case, floors of the tunnels form a walkway for the passengers between the platform of the terminal building and an entrance of the aircraft in the airport.
Adjacent tunnels with an outer-inner-tunnel relation are telescopically fitted to each other. In this structure, a stepped portion is formed in the walkway constituted by these tunnels. This impedes smooth walk of the passengers (travelers). Under the circumstances, a stepless structure of the walkway for eliminating the stepped portion has been proposed.
For example, Patent Literature 1 discloses a configuration in which the outer tunnel of the adjacent tunnels includes a walkway section comprised of a plurality of floor plates coupled to each other, and this walkway section is moved to the underside of the floor of the inner tunnel. Patent Literature 1 discloses in FIGS. 14 to 16 a configuration in which a plurality of extension/retraction support shafts (indicated by reference symbol “3” in the drawings) which are rotatable to support a walkway section, are arranged in the lengthwise direction (longitudinal direction) of the outer tunnel, at a location that is inward of the outer tunnel.